NYCDEP Kensico Flow Control Improvements

The Delaware Effluent Chamber at Kensico Reservoir (Shaft 18) is where water reenters the Delaware Aqueduct on its way to Hillview. Shaft 18 is equipped with two 5 x 15 foot roller gates and three 60 inch cone valves which directly connect to the reservoir downtake shaft as well as fifteen sluice gates which control flow to the Delaware Aerator and the Aqueduct. The mitigation measures installed earlier to tackle the problem of cavitation, had limited success; i.e. cavitation at the cone valves is still a problem and the capacity of the aqueduct system was diminished. During critical high consumption periods, typically in the summer, demand in the distribution system exceeds flow capacity from Kensico. The marginal difference between demand and capacity is made up from storage at Hillview. When half of Hillview is taken out of service for construction of its cover, the lost capacity will be made up by restoring the Delaware Aqueduct between Kensico and Hillview to its original capacity. 

Flow Control Modifications – Shaft 18
The new flow control structure incorporates vanes located in the Kensico Aerator No. 2 embankment. The flow control structure connects the aerator’s supply side and discharge side conduits. The installation of this new structure renders the aerator inoperable. The new structure includes access man-ways for inspection of the structure and accompanying supply conduits as well as stop plank grooves with removable concrete planks at the ground elevation for isolation of the supply conduit sluice gates. The structure also includes a connection with piping and a blind flange for a future drinking water connection for the Town of Mount Pleasant and a similar connection for a water supply to a future water fountain in the existing Aerator. The new flow control structure provides the City with the much needed redundancy for delivering flow to the Delaware Aqueduct and Hillview Reservoir as well as additional alternatives for flow control. Flow is delivered from the fore-bay of the Shaft 18 Effluent Chamber into the new flow control structure via ten supply side conduits. 

Flow Control Modifications – Shaft 19 
It consisted of removal of the existing concrete weirs and provision of a new vent structure at the shaft .These modifications helped reducing the head losses through the structure, and increased the flow discharge capacity of the aqueduct.